Experimental frameworks for evaluating net effects of hydrologic service payments on coupled social-ecohydrological systems

As global concern over water scarcity and declining water quality grows, payment for hydrological services (PHS) programs, whereby land users receive payments in exchange for adopting practices favorable to water resources, offer a potential solution for ensuring clean and plentiful water. However, because PHS programs seek to influence both human behavior and the environment, they are extremely complex, and the scientific understanding needed to maximize their effectiveness is lacking. The goal of this project is to analyze the interacting social, economic, ecological, hydrological and policy impacts of Mexico's PHS programs, which have been operating for over a decade and thus represent some of the longest running programs of their kind in the world. The project will focus on two types of PHS programs operating within the Pixquiac and Gavilanes watersheds near Xalapa and Coatepec, Veracruz: 1) the "national" program, which is centrally organized and administered by the Mexican government, and 2) the local "matching" program, which requires greater involvement of diverse local institutions in the financing, planning, and execution of the program. Impacts of the PHS programs on water and other (e.g., biodiversity, carbon) ecosystem services will be assessed using a combination of field data collection and modeling. Interviews and surveys will be used to assess the influence of the two PHS programs (national and local) on people's decisions, as well as interactions with other social qualities such as perceptions of equity and well-being, health, income opportunities, and social organization. The information collected for the human and natural systems will be integrated through the application of spatial mapping tools, watershed modeling, and participatory workshops involving multiple actors in order to identify the key factors that determine the long-term success and cost-benefit trade-offs of PHS programs. This integrated approach will also be used to test the effects of different PHS policy and land use change scenarios on ecosystem services and long-term watershed sustainability. 

This project will contribute significantly to enhancing society's ability to protect water resources by developing an interdisciplinary approach for understanding how PHS policies both shape - and are shaped by - the coupled human and natural systems they seek to influence. Additionally, an important aspect of this research is that it will advance the current level of knowledge about PHS programs to encompass the larger concept of watershed sustainability, which to date has not been an integral component of PHS yet is crucial to protecting water resources. Results will be integrated into two science-based decision support tools that can be used by landowners and decision makers achieve desired watershed management and policy goals while avoiding unintended consequences: an aggregate sustainability index that provides concise information on watershed health, and a GIS-based mapping framework that spatially integrates impacts of land use change on ecosystem services and their relationship with coupled human and natural systems. Given that PHS programs are rapidly becoming an important policy mechanism worldwide for addressing critical environmental issues related to water supply and quality, the findings from this research will have broad impacts by helping to guide the design of more effective PHS policies across the globe. To ensure successful local and global application of this research, findings will be widely disseminated through diverse portals, including policy forums, news media, interdisciplinary and disciplinary scientific journals, an edited book volume on global PHS programs, and a series of educational modules and seminars developed for both the middle school and university levels. Finally, this project will train and mentor one postdoctoral research associate, four graduate students, and several undergraduate students, all of whom will gain valuable skills in interdisciplinary thinking and analysis and sustainability science within the context water resource management.


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